Method of making roads, pavements, and the like.



- p s'ra'ras A v WALTER E. HASSAM, OF WORCESTER, MASSACHUSETTS, ASSIGNOR TO HASSAM PAVING COMPANY, A QOQPOEATION MASSACHUSETTS.

METHOD MAKING ROADS, PAVEMENTS, ANT) THE LIKE.

Patented Feb. 6, 1917.

W 1,215,273,; Specification of Lctter s Patent.

No Drawing.

To all whom it may concern:

Be it known that I, WALTER E. HAssAM,

1 .1. apply to the surface an emulsified bitumia citizen of the United States, residing at Worcester, in the county of Worcester State of Massachusetts, have invented a new and useful Method-of Making Road's, Pav. ments, and thelike, 'of which the following} isaspecification. 7

The principal object-of this inventio V to provide an improved wearing surface for the type of pavement known as the Hassam.

pavement, of which I am the inventor.

' Several types of surface coatings have been suggested and used, butforvarious reasons they usually have to be laced on the Hassam pavement only after t e cement grouting has dried and hardened, and the same condition prevails when these coatings were placed on pavements made of ordinary Moreover it has proved cement concrete. Y practically impossible to make the old coatings absolutely impervious. Therefore water frequently gets down under them in placesand freezes and thaws. This causes the top or cover layer to heave and eventually become loosened in spots which causes the road. to break down. Intense summer heat also softens the ordinary coatings and causes them to creep.

V It is well known that most types of these pavements set in a stronger condition and are subject to less danger from fissuresnnd cracks, so that they are 'moref durable, if after the pavement is laid a'coating ofloam, sand or other protecting material is" applied and left for a period of aboutten days to prevent the greenpavement' being subjected tothe action of the sun, as well as the wind and rain. In'fact in many States now the specifications are systemmatically prepared in such a way as to necessitate the use of this method. i One of the objects of this invention is to provide an improvement in the Hassam pavement which will permit of the application of the surface coating directly on the wet and plastic routing the day it islaid without waiting or it to harden, and which will in itself constitute a protecting coating during the drying and hardening of the grouting, so that the expense and delay ne-' cessitated by. the above mentioned temporary covering process will be avoided.

I accomplish this result by making a pavement in the "usual manner employed inlay- Application ii leginovember 29, 1915. SeriaLNo. 63,954.

ing the Hassam pavement, but instead of the surface treatments heretofore suggested nous coating in a cold condition while the grouting is in a Wet and plastic state. More specifically the method of procedure'which Prefer is'as follows sllagreada layer of aggregate material, prefa ly'j-in' theform of uncoated stone, on'the" the voids are reduced materially. Then I' apply tol it ,a thin grouting of cement, sand and Waterin a creamy condition. This'is poured over the surface and allowed to sink down in and fill the voids and .1 supply enough so that'it comes substantially tothe surface of the layer of stone. As so far described I proceedaccording to the method In the first place after excavating as usual,

' i I I c o I I foundation and roll 1t in its dry state until -1t11s compacted as much as ossible, so that laid down in my own prior patents for the 1 making of the so-called Hassam pavement, but while the outing is in its wet state and While it is su stantially at a uniform level I- place upon it a layer formed of aggregate material, emulsified bitumen and Portland cement, 'the aggregatematerial preferably involving brokenstone and sand. The proportions may conveniently beras follows Stone 12 parts, cement 1 part, sand six parts,-

and suflicient bitumen about two parts 'li0 f coat all the stone. These -materials are thoroughly incorporated together so that the sand and stone are covered throughout their surfaces by the mixture of emulsified bitumen and cement, and then a layer of this material in acold state is placed on the wet surface of the grout, said layer being one or two inches thick or more as may be desired. Finally I roll the whole surface to force the upper layer of broken stone into the grouting while the latter is still wet and before it has commenced to set. This is important, because if the grouting is disturbed after it has commenced to set it will set in a weak condition and never have the strength and durability that it has when operated so that thereafter it is free to solidify and harden without the expression of any material further amount of moisture. Of course this rolling operation also solidifies the bituminous layer and furnishes a smooth hard surface for the road bed.

I am aware of the fact that it has been proposed before to use emulsified bitumen in combination with broken stone, sand and cement as a surface layer for an ordinary dation after long usagesaid top layer can cement concrete pavement, but owing to the fact that it has to be rolled in order to make it of value and the further fact that the cement concrete when in its plastic state cannot be 'rolled adequately so as to bring it to a uniform surface, that method has not proved a practical one so far as I am aware.

It is practical when applied in the way described herein because the first compacted stone layer is strong enough to stand the passage of the heaviest road roller .over it without forcing the stones out in front and at both sides as is the case with the cement concrete pavement.

By rolling the stone coated with emulsified'asphalt and cement into the top of .the grouting while still in areceptive state as described above the setting of the grouting is materiallymodified; Instead-of simply having its moisture evaporated into the air slowly and setting in a period of several days by evaporation and gravity alone it is cement grouting, and consequently does away with the expensive and delaying op eration of covering the pavement with a temporary protecting cover.

Among the other'advantages of this invention are the following :A top layer or wearing surface is provided which .can be applied to a 'Hassam ffoundation so that said top layer will actually combine therewithsaid top layer will be durable in all. kinds of weather-said top layer will remain in its original position on the Hassa-m founbe laid and repaired easily without sln'lled labor-said top layer will not disintegrate ,to form dust-said top layer will have a good appearance-said top layer will make the pavement practically noiseless,said top layer can be laid on the Hassam foundation in damp or even rainy or slightly freezing weather so that time can be saved under certain weather conditions.and said top layer will have substantially the same rate of expansion and contraction as the Hassam foundation, whereby deterioration of the while in a liquid state pavement by reason of internal strains and stresses will be much reduced.

Another way in which the method can be carried out from the point at which the grouting is applied is as follows :Over the grouting can be applied a layer of uncoated broken stones and these can be rolled into the grouting. vThen a mixture of emulsified bitumen, Portland cement and sand in a comparatively thin state can be poured over the same and again rolled.

Although I have illustrated and described only two ways of proceeding I am well aware of the fact that other modifications in the manner of carrying out the process can be made without departing from the scope of the invention as expressed in the claims. Therefore I do not wish to be limited to all the details of procedure herein described, but what I do claim is: v

1. The method of making a pavement or the like, which consists in spreading a layer of uncoated aggregate material, rolling it until the voids are small, applying to it a thin cement'grouting until the voids are filled, and the grouting seeks its level substantially at the surface of said layer of ag gregate material, then while said grouting is in its wet state and before its surface has :been disturbed placing upon it a layer formed of a mixture of aggregate material, emulsified bitumen, and Portland cement thoroughly incorporated together, and finally rolling.- b

2. The method of making a pavement or of uncoated broken stone, rolling it until the voids are small, applying to it a thin cement grouting in a creamy state until the'voids are filled and the grouting rises to the top of the layer of stone, then before the grouting commences to set placing upon it a layer formed of a mixture of broken stone, emulsified bitumen, Portland cement, and sand thoroughly incorporated together, finally rolling to force the upper layerof broken stone into the grouting while still wet, force the surplus moisture directly out of the grouting and up through the bituminous layer and solidify said bituminous layer.

3. The method of making a pavement or the like which consists in spreading-a layer of dry, uncoated, broken stone on a foundation, rolling it to compact it throughout and bring its top surface into a uniform condition, pouring upon it a thin cement grouting in a creamy state until the voids among the stones are filled and the grouting, rises substantially to the top of the stone layer, then before the grouting commences to set and cold state a thin layer formed of a mixture of broken stone, emulsified bitumen, Portland cement, and sand thoroughly incorporated together, and rolling to force the upper layer 180 placing upon it in a the like, which consists in spreading a layer a into the grouting while still Wet and before it has commenced to set. 4 I o 4. The method of making a pavement or the like which consists in spreading a base 'layer of dry, uncoated, broken stone on a foundation, rollingit to compact it throughout and bring its top surface into a uniform condition, pouring upon it a thin cement grouting in a creamy state until the voids among the stones are filled, then placing upon said layer in a cold state a layer formed ofia mixture of broken stone, emulsified bitumen, Portland cement, and sand, thoroughly incorporatedtogether, and rolling to force the upper layer into the base layer while still Wet.

5. A, pavement having a base layer of hard, rolled, uncoated stone and a grouting of cement filling the voids therein, and a top layer formed of a mixture of broken stone, emulsified bitumen,-Portland cement, and sand thoroughly incorporated together and united with the base layer.

6 A pavement having a hard, rolled, uncoated stone and a grouting of cement filling the voids therein, and a top layer formed of about twelve parts broken stone, one part Portland cement, six

partssand, and tWo parts emulsified'bitumen incorporated together andunited With the baseQlayer.

In testimony whereof I have hereunto set my hand.

WALTER E. HASSAM.

base layer of 

